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Zero-frequency critical bulk viscosity: is the amplitude ratio truly universal?
1Department of Theoretical Physics, Indian Association for the Cultivation of Science, Jadavpur, Calcutta 700 032, India.
Summary
Sound attenuation data reveals a universal amplitude ratio near 0.18, close to previous estimates. However, this ratio is not truly universal and exhibits logarithmic corrections.
Area of Science:
- Physics
- Thermodynamics
- Fluid Dynamics
Background:
- The zero-frequency bulk viscosity is theoretically linked to a universal amplitude ratio.
- Previous calculations by Onuki estimated this universal number to be approximately 0.10.
Purpose of the Study:
- To investigate the sound attenuation data for extracting the universal amplitude ratio.
- To re-evaluate the universality of the amplitude ratio associated with zero-frequency bulk viscosity.
Main Methods:
- Analysis of sound attenuation data.
- Calculation of the amplitude ratio from experimental data.
- Theoretical reconsideration of the amplitude ratio's universality.
Main Results:
- Sound attenuation data yields an amplitude ratio value around 0.18.
- This value is in reasonable agreement with Onuki's theoretical estimate.
- The amplitude ratio is found to possess logarithmic corrections, indicating it is not strictly universal.
Conclusions:
- Sound attenuation data provides a viable method for estimating the bulk viscosity amplitude ratio.
- The universality of the amplitude ratio is challenged by the discovery of logarithmic corrections.
- Further research is needed to fully understand the implications of these corrections in fluid dynamics.